Kristen Stewart, Robert Pattinson SPLIT: 'Twilight' Lovers Break Up (Again) After Heated Fights, K-Stew 'Heartbroken,' Still Living Together 'Because of Dogs?'

Several gossip reports confirm that "Twilight" lovebirds Kristen Stewart and Robert Pattinson have officially broken up (yet again). Apparently, trouble began when the couple got into a heated fight on R-Patz's 27th Birthday (May 13)... things continued to spiral downhill ever since. Insiders claim that K-Stew is utterly sad and heartbroken over the split. Still, the duo remains living together for the sake of their pet dogs... and close pals of the stars insist that the seperation will likely be "short-lived."

Rumors of an inevitable 'Robsten' break up have been swirling online for months:

Kristen Stewart and Robert Pattinson Fight On R-Patz Birthday? 'Parties' with Katy Perry, 'Twilight' Sweetheart Jealous, Break Up Soon?

Robert Pattinson and Kristen Stewart Update: R-Patz 'Cozies Up' with K-Stew's Bestie Katy Perry? Friends Approve of 'New' Romance

Kristen Stewart, Robert Pattinson S*x Life Suffering? 'Twilight' Sweethearts Shack-Up with K-Stew's Mom Jules during Divorce, R-Patz 'Hates It'

Robert Pattinson 'Laughs Off' Kristen Stewart, Rupert Sanders Cheating Rumors, Pranks 'Twilight' Sweetheart with Lie Detector Test Threat

Kristen Stewart and Robert Pattinson: Katy Perry Threatens 'Twilight' Relationship? John Mayer's Ex 'Would Date R-Patz' if Couple Split

Kristen Stewart, Robert Pattinson Spend Romantic Beach Easter Together, Malibu: R-Patz 'Parties Solo' in LA, Takes Break from 'Clingy' K-Stew

Kristen Stewart, Robert Pattinson 'Barely Talking': K-Stew Makes Out with Garrett Hedlund, R-Patz gets Down and Dirty with Guy Pearce [VIDEO]

But apparently things really came to a head when K-stew planned a "special birthday surprise" for R-Patz... and he totally ditched to hang out drink with his friends.

An insider tells E! News that the root of the "temporary" seperation is "priorities" -  the duo tried to work out their issues up until Saturday (May 18). But for now, breaking up was "the best for the time being."

As most fans remember, the couple split back in July when K-Stew cheated on her "Cosmopolis" beau with "SWATH" director, Rupert Sanders. Robsten eventually rekindled a relationship and have been together ever since... until now.

The pair was last spotted together at LAX on May 8. 

K-Stew's taking the split rather hard. One source tells People, "Kristen has been in a terrible mood... It was obvious that things were not great with Rob... She hasn't left the house for days [and] has surrounded herself with friends 24/7."

Odd, considering R-Patz is apparently still living with her. "They are going to stay living at Kristen's house because of the dogs," The E! insider explains. "It's not fully over or he would have moved out." 

Several people close with the situation agree that "they will be back together in no time." What do Mstars readers think about the break up news?